Exhaust gas is a byproduct of fuel combustion. Often times exhaust gas is vented to the atmosphere via an exhaust stack. Factories, for example, may have one or more tall exhaust stacks to vent exhaust gas to the atmosphere. The exhaust gas is typically at a relatively high temperature when released and includes a certain amount of moisture and other chemicals that may condense when cooled. As the exhaust gas mixes with cooler atmospheric gases, when exiting the exhaust stack, the exhaust gas cools, reaching an equilibrium temperature with the atmosphere. When the exhaust gas cools often it will sink below a saturation temperature for the moisture or other chemicals. When a saturation temperature is reached, the moisture or other chemicals begin to condense, often forming plumes or clouds. These plumes or clouds are often perceived by the local population as pollution or smoke, even when the plume or cloud is made up almost entirely of water vapor. As a result, minimizing plume formation from exhaust stacks may be desirable to reduce a perception that the exhaust stack is polluting the local atmosphere.
Certain types of industrial operations are more likely to produce exhaust moisture plumes, for example, fluid or wastewater concentration/evaporation operations. In one example, concentrating landfill leachate may include evaporating or vaporizing a liquid portion of the leachate to reduce the overall volume of the leachate. As a result, a landfill operator is left with a lower volume of leachate that requires disposal. Because a large volume of liquid is evaporated in the concentrating process, exhaust gases from such concentrating operations include a large percentage of moisture or water vapor, which may approach the saturation point of the exhaust gas as the exhaust gas cools upon exiting to the atmosphere. In such concentrating operations, when the saturated exhaust gas exits an exhaust stack and enters the atmosphere, the moisture almost immediately begins to condense, forming moisture plumes. Other evaporation processes, such as the process of evaporating water in a cooling tower, also may produce moisture plumes when gas exits to the atmosphere.